The present invention relates to a device and a process for determining the jaw position when preparing a full denture, i.e. a set of upper and lower dentures, or one of upper and lower full dentures.
When a full denture is prepared, because the original occlusion before the extraction of teeth cannot be accurately known, it is very difficult to reproduce the optimum upper and lower jaw positions including the motion of muscles supporting the jaws. Therefore, in a conventional process, the jaw position is determined only on the basis of the dentist's experience.
More specifically, in the conventional process, the dentist makes base plates which correspond to the upper and lower jaws of the patient, he mounds wax on both base plates to form wax occlusion rims, and sets those base plates to the patient's mouth.
Then, the dentist gets the patient to repeat biting motions. By adjusting the height of the wax occlusion rims while observing the chewing or biting motion of the patient and his reaction, the dentist determines a jaws position which seems to be optimum.
The above-mentioned conventional process has disadvantages in that it is difficult to obtain an ideal jaw position since the determination is only entrusted to the dentist's judgement and that considerable experience is required of the dentist to find an exact jaw position. Then, in practice, in many cases, the ideal jaw position (i.e. original jaw position before extraction of teeth) cannot be accurately reproduced, and thus the patient cannot experience comfortable chewing and biting motion again.
The object of the present invention is to overcome the above-mentioned problem, and to provide a device and process capable of reproducing the optimum jaw position. Particularly, it has been noticed that the ideal jaw position provides the maximum biting pressure. Therefore, a device and a process capable of determining the ideal jaw position can be realized based on observing the maximum value of the pressure.